Acts 1:3-8

to whom he also showed himself alive after his passion by many proofs, appearing unto them by the space of forty days, and speaking the things concerning the kingdom of God: and, being assembled together with them, he charged them not to depart from Jerusalem, but to wait for the promise of the Father, which, said he, ye heard from me: for John indeed baptized with water; but ye shall be baptized in the Holy Spirit not many days hence. They therefore, when they were come together, asked him, saying, Lord, dost thou at this time restore the kingdom to Israel? And he said unto them, It is not for you to know times or seasons, which the Father hath set within his own authority. But ye shall receive power, when the Holy Spirit is come upon you: and ye shall be my witnesses both in Jerusalem, and in all Judæa and Samaria, and unto the uttermost part of the earth.